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b=aHGV8ioIOvddcAtewqb4hGh5f7g1CTeL0/3RgSjclKplWSCHhJxvVr+7LA9tUkY3W CyYjk3PnBbDhEzexWTulCBZ2q0p9mgr1MtrYcRHzay7W9H51gBEzLv/PGQ0wp10tgk yd5iIEEm9NaBTYzucXFmllfgzNo5pcFOMphosVdep+mfDYls9Z5PjAqYXZqIcSrxh8 5q1ML6kcDiyxJYE9RWXX16FRKv5nrnqR6/9u2iRLtey2zCJKbM2FanQpKrNvR+UAaZ xeJ6g/0xf7wKPRr2NNHdgMmEO6o9GgfW8JztKEKdT6sEmrto2y2YI7GGOgv8LwPo4u 1A9zeVlDpoGgw== From: "Mike Rapoport (Microsoft)" Date: Mon, 07 Sep 2026 13:23:44 +0300 Subject: [PATCH 03/13] s390/chsc_sch: Use kzalloc() for CHSC requests MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260907-s390-cio-ready-v1-3-ca7f39806234@kernel.org> References: <20260907-s390-cio-ready-v1-0-ca7f39806234@kernel.org> In-Reply-To: <20260907-s390-cio-ready-v1-0-ca7f39806234@kernel.org> To: Heiko Carstens , Vasily Gorbik , Alexander Gordeev Cc: Christian Borntraeger , Mike Rapoport , Peter Oberparleiter , Sven Schnelle , Vineeth Vijayan , Vlastimil Babka , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org X-Mailer: b4 0.17-dev X-Stat-Signature: ya98k6de9pujs1yditdphk8eur7ss3dx X-Rspamd-Queue-Id: 22E5580003 X-Rspamd-Server: rspam02 X-Rspam-User: X-HE-Tag: 1788776643-739602 X-HE-Meta: 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 OcNeDmoU hXFsgIBsXQS4w3VpTIM/Cxen1G5ggWaCPNCGDidslEpuR/cbJ/W9GWKPWI6dEHmHDHsfNhOWn8FZgmVllMqzuloFFudDyI0H6ZC+/CiZ1/aYYlNuurS1F3ciJO8EPbD1iMA7REv44btcIS5yydidjZIlY3J75vU99tWdV1fqlEwg0OHNOyHilF/zLcVfr6SbgR2TFYeD5RPOvH+H3U62GIDcJyWB4aNU5T9E9Nn+Clpv77jQ3A8kd7hl+uaYvSSmrgpGddkkrfqYztlSmO4siXyFwLq6GDfaml4MgUyuHxmV4PSmnVtAbnZeZXjcQOadEaBnL Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: The CHSC ioctl handlers allocate request and response areas for CHSC commands issued on behalf of userspace. This memory can be allocated with kmalloc() as there's nothing special about it to go directly to the page allocator. kmalloc() provides a better API that does not require ugly casts and kfree() does not need to know the size of the freed object. Performance difference between kmalloc() and __get_free_pages() is not measurable as both allocators take an object/page from a per-CPU list for fast path allocations. For the slow path the performance is anyway determined by the amount of reclaim involved rather than by what allocator is used. Replace use of get_zeroed_page() with kzalloc() and free_page() with kfree(). Link: https://lore.kernel.org/all/635405e4-9423-4a25-a6e7-e03c8ea0bcbe@redhat.com Assisted-by: copilot:claude-opus Signed-off-by: Mike Rapoport (Microsoft) --- drivers/s390/cio/chsc_sch.c | 44 ++++++++++++++++++++++---------------------- 1 file changed, 22 insertions(+), 22 deletions(-) diff --git a/drivers/s390/cio/chsc_sch.c b/drivers/s390/cio/chsc_sch.c index b6cb8bb8bcc4b..c8d6871d1841e 100644 --- a/drivers/s390/cio/chsc_sch.c +++ b/drivers/s390/cio/chsc_sch.c @@ -292,7 +292,7 @@ static int chsc_ioctl_start(void __user *user_area) if (!css_general_characteristics.dynio) /* It makes no sense to try. */ return -EOPNOTSUPP; - chsc_area = (void *)get_zeroed_page(GFP_DMA | GFP_KERNEL); + chsc_area = kzalloc(PAGE_SIZE, GFP_DMA | GFP_KERNEL); if (!chsc_area) return -ENOMEM; request = kzalloc_obj(*request); @@ -321,7 +321,7 @@ static int chsc_ioctl_start(void __user *user_area) snprintf(dbf, sizeof(dbf), "ret:%d", ret); CHSC_LOG(0, dbf); kfree(request); - free_page((unsigned long)chsc_area); + kfree(chsc_area); return ret; } @@ -340,7 +340,7 @@ static int chsc_ioctl_on_close_set(void __user *user_area) ret = -ENOMEM; goto out_unlock; } - on_close_chsc_area = (void *)get_zeroed_page(GFP_DMA | GFP_KERNEL); + on_close_chsc_area = kzalloc(PAGE_SIZE, GFP_DMA | GFP_KERNEL); if (!on_close_chsc_area) { ret = -ENOMEM; goto out_free_request; @@ -353,7 +353,7 @@ static int chsc_ioctl_on_close_set(void __user *user_area) goto out_unlock; out_free_chsc: - free_page((unsigned long)on_close_chsc_area); + kfree(on_close_chsc_area); on_close_chsc_area = NULL; out_free_request: kfree(on_close_request); @@ -375,7 +375,7 @@ static int chsc_ioctl_on_close_remove(void) ret = -ENOENT; goto out_unlock; } - free_page((unsigned long)on_close_chsc_area); + kfree(on_close_chsc_area); on_close_chsc_area = NULL; kfree(on_close_request); on_close_request = NULL; @@ -392,7 +392,7 @@ static int chsc_ioctl_start_sync(void __user *user_area) struct chsc_sync_area *chsc_area; int ret, ccode; - chsc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + chsc_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!chsc_area) return -ENOMEM; if (copy_from_user(chsc_area, user_area, PAGE_SIZE)) { @@ -414,7 +414,7 @@ static int chsc_ioctl_start_sync(void __user *user_area) else ret = 0; out_free: - free_page((unsigned long)chsc_area); + kfree(chsc_area); return ret; } @@ -438,7 +438,7 @@ static int chsc_ioctl_info_channel_path(void __user *user_cd) u8 data[PAGE_SIZE - 20]; } __attribute__ ((packed)) *scpcd_area; - scpcd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + scpcd_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!scpcd_area) return -ENOMEM; cd = kzalloc_obj(*cd); @@ -476,7 +476,7 @@ static int chsc_ioctl_info_channel_path(void __user *user_cd) ret = 0; out_free: kfree(cd); - free_page((unsigned long)scpcd_area); + kfree(scpcd_area); return ret; } @@ -500,7 +500,7 @@ static int chsc_ioctl_info_cu(void __user *user_cd) u8 data[PAGE_SIZE - 20]; } __attribute__ ((packed)) *scucd_area; - scucd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + scucd_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!scucd_area) return -ENOMEM; cd = kzalloc_obj(*cd); @@ -538,7 +538,7 @@ static int chsc_ioctl_info_cu(void __user *user_cd) ret = 0; out_free: kfree(cd); - free_page((unsigned long)scucd_area); + kfree(scucd_area); return ret; } @@ -563,7 +563,7 @@ static int chsc_ioctl_info_sch_cu(void __user *user_cud) u8 data[PAGE_SIZE - 20]; } __attribute__ ((packed)) *sscud_area; - sscud_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + sscud_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!sscud_area) return -ENOMEM; cud = kzalloc_obj(*cud); @@ -602,7 +602,7 @@ static int chsc_ioctl_info_sch_cu(void __user *user_cud) ret = 0; out_free: kfree(cud); - free_page((unsigned long)sscud_area); + kfree(sscud_area); return ret; } @@ -625,7 +625,7 @@ static int chsc_ioctl_conf_info(void __user *user_ci) u8 data[PAGE_SIZE - 20]; } __attribute__ ((packed)) *sci_area; - sci_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + sci_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!sci_area) return -ENOMEM; ci = kzalloc_obj(*ci); @@ -662,7 +662,7 @@ static int chsc_ioctl_conf_info(void __user *user_ci) ret = 0; out_free: kfree(ci); - free_page((unsigned long)sci_area); + kfree(sci_area); return ret; } @@ -696,7 +696,7 @@ static int chsc_ioctl_conf_comp_list(void __user *user_ccl) u32 res; } __attribute__ ((packed)) *cssids_parm; - sccl_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + sccl_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!sccl_area) return -ENOMEM; ccl = kzalloc_obj(*ccl); @@ -745,7 +745,7 @@ static int chsc_ioctl_conf_comp_list(void __user *user_ccl) ret = 0; out_free: kfree(ccl); - free_page((unsigned long)sccl_area); + kfree(sccl_area); return ret; } @@ -756,7 +756,7 @@ static int chsc_ioctl_chpd(void __user *user_chpd) int ret; chpd = kzalloc_obj(*chpd); - scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + scpd_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!scpd_area || !chpd) { ret = -ENOMEM; goto out_free; @@ -775,7 +775,7 @@ static int chsc_ioctl_chpd(void __user *user_chpd) ret = -EFAULT; out_free: kfree(chpd); - free_page((unsigned long)scpd_area); + kfree(scpd_area); return ret; } @@ -796,7 +796,7 @@ static int chsc_ioctl_dcal(void __user *user_dcal) u8 data[PAGE_SIZE - 36]; } __attribute__ ((packed)) *sdcal_area; - sdcal_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA); + sdcal_area = kzalloc(PAGE_SIZE, GFP_KERNEL | GFP_DMA); if (!sdcal_area) return -ENOMEM; dcal = kzalloc_obj(*dcal); @@ -834,7 +834,7 @@ static int chsc_ioctl_dcal(void __user *user_dcal) ret = 0; out_free: kfree(dcal); - free_page((unsigned long)sdcal_area); + kfree(sdcal_area); return ret; } @@ -904,7 +904,7 @@ static int chsc_release(struct inode *inode, struct file *filp) } snprintf(dbf, sizeof(dbf), "relret:%d", ret); CHSC_LOG(0, dbf); - free_page((unsigned long)on_close_chsc_area); + kfree(on_close_chsc_area); on_close_chsc_area = NULL; kfree(on_close_request); on_close_request = NULL; -- 2.53.0